From the state of the art, it is known to control (open loop and/or closed loop) the transmission functions via an electronic control apparatus. In this connection, reference can be made, for example, to the publication "Bosch Automotive Handbook", 3rd edition, pages 548 to 551. A differential transmission (axle differential) is arranged between the transmission and the driven wheels and has a specific rpm ratio. The transmission ratio of the axle differential transmission is a quantity which is used in an electronic transmission control in order, for example, to determine the transmission output rpm from the wheel rpms when a transmission output rpm sensor is defective.
It is conventional to build in differential transmissions having different differential transmission ratios into different vehicle models of a series of vehicles. If one would have to provide these different differential transmission ratios in the software of the transmission control apparatus, then this would cause increased complexity because of the different software for the individual vehicle models. In order not to have to provide the differential transmission ratio in the software, a function is integrated into the transmission control apparatus via which the built-in differential transmission ratio can be learned.